The present invention relates to aqueous dispersions of polyurethanes having polyfluorooxetane segments or moieties therein and further to coatings made from such dispersions. These protective coatings when applied to a polymeric substrate and crosslinked, exhibit good resistance to moisture, abrasion resistance, stain resistance, chemical resistance, and low coefficient of friction properties. Surprisingly, the coating of the present invention generally has a lower coefficient of friction at lower fluorine levels than other fluorine containing polymers. The invention also relates to blends of the polyurethane aqueous dispersion containing vinyl ester monomers which can be subsequently polymerized by radiation to form a comingled blend of polymers.
U.S. Pat. No. 5,447,982 to Kamba et al. relates to a process for preparing an aqueous dispersion, which comprises subjecting a monomer to emulsion polymerization in an aqueous medium in the presence of a fluorine-containing copolymer comprising units derived from a fluoroolefin, and units having a hydrophilic side chain.
U.S. Patent No. 5,464,897, Das et al., relates to an aqueous fluorocopolymer dispersion prepared by aqueous dispersion polymerization of a) a dispersed phase containing a fluoroolefin monomer component and a vinyl ether monomer component in the presence of b) a base neutralized, aqueous dispersion of a polymeric dispersant having an acid value of at least 1.5 mg KOH/gram not exceeding about 35 mg KOH/gram and the amount of neutralizing base does not exceed about 10 percent based on resin solids of the dispersant.
Japanese Publication 04,131,165 relates to a waterborne base coat of internally-crosslinked resin particles as binders, and pigments; and a waterborne clear coat containing fluoropolymer binders. Thus, an Al panel was sprayed with a colored aqueous solution containing allyl methacrylate-Bu acrylate-acrylic acid-hydroxyethyl methacrylate-Me methacrylate copolymer particles, set at 80. degree. for 15 min, covered with an aqueous clear solution containing acrylate-methacrylic acid-2-methacryloyloxyethyl isocyanate-chlorotrifluoroethylene-cyclohexyl vinyl ether-Et vinyl ether-hydroxybutyl vinyl ether copolymer binder, and baked at 160. degree. for 25 min to give a surface with 60. degree.-gloss 94%, and water (240 h, 40.degree.H2O) and weather (2000 h) resistance.
Japanese Publication 06,145,598, relates to coatings, having lubricity, contain polyurethanes prepared from polyisocyanates and fluoro oxyalkylenes containing 2 active H atoms. An aqueous composition containing adipic acid-ethylene glycol-isophthalic acid-neopentyl glycol-terephthalic acid-dimethylolpropionic acid-Fomblin Z Doltx 2000 (perfluoro polyether polyol)-Coronate T 80 block copolymer gave films with water contact angle 101.degree., vs. 103, 62, and 0.35, resp., for a film prepared similarly without the Fomblin Z Doltx 2000.
Japanese Publication 06,287,548, K. Ito et al. relates to an aqueous coating composition containing a polyurethane resin which is obtained by reacting, as essential reactants, a compound having fluorinated oxyalkylene units and at lease two active hydrogen atoms (e.g. a hydroxyl-and/or carboxyl-terminated fluoropolyether having a molecular weight of 500-7,000) with a polyisocyanate (e.g. 2,4-toluene diisocyanate). The composition can be used for surface lubricity and wear resistance, and oil repellency, antifouling properties, blocking resistance, and adhesiveness.
Japanese Publication 07179809, K. Shinichi et al., relates to dispersions, which are crosslinkable with water-based hardeners and provide coatings with weatherability, contain polymers including (A) units based on fluoroolefins, (B) units comprising hydrophilic group-containing macromonomers, and (C) units from OH-substituted monomers XYZ (X=radically polymerizable unsatd. Group; Y=C. 5 linear, branched, or alicyclic group-containing Alkylene-containing divalent linking groups; Z=OH). Thus, cyclohexyl vinyl ether 16.6, Et vinyl ether 16.4, CH2;CHOCH2C6H10CH20 (CH2CH20) n H 3.8, and chlorotrifluoroethylene 52.7 g in water contg. K2CO3, NaHSO3, ammonium persulfate, Newcol 1110 (nonionic emulsifier), and Na lauryl sulfate were reacted at 30xc2x0 for 12 h to give a latex showing prevention of coagulation in homogenizing.
WO Publication 99/26992 relates to coatings which have low surface energies provided by fluorine and/or silicone moieties. Aqueous dispersions of externally chain extended polyurethane compositions terminated by hydrolyzable and/or hydrolyzed silyl groups and containing dispersing or emulsifying groups, particularly carboxyl groups are provided. Also polyurethane dispersions which are substantially organic solvent free which cure to water are provided. The compound RfRxe2x80x2fCFCOOCH2C(R)(CH2OH)2 is provided.
U.S. Pat. No. 5,780,117 relates to radiation-curable latex compositions having a secondary curing mechanism. In these compositions, an anionically stabilized, water-borne dispersion of one or more radiation-curable resins is combined with a low molecular weight compound having at least two reactive functional groups, wherein one reactive functional group comprises an epoxy and the other reactive functional group comprises either an epoxy or a functionality capable of self-condensation after film formation. Also disclosed is a method for providing a cross-linked protective coating on a substrate, wherein a coating of the composition of the present invention is applied to the substrate, the coated substrate is exposed to actinic radiation to effect curing, and then the unexposed or underexposed portions of the coated substrate are allowed to cure at room temperature or greater.
European Disclosure 00331409 relates to a process for producing a polyester film having a thin cured polyurethane coating, which comprises (1) applying an aqueous composition comprising a thermosetting polyurethane prepolymer as a film-forming component to at least one surface of an unoriented aromatic polyester film to form a thin wet coating on it, said polyurethane prepolymer being characterized by (i) having a polyol component at least 10% by weight of which is composed of a polyol containing a carbon-carbon double bond selected from unsaturated polyester polyols and polybutadiene polyols, the carbon-carbon double bond being cleavable under ultraviolet light, (ii) having a pendant anionic hydrophilic group in the polymer chain, and (iii) having isocyanate groups blocked with an oxime at the ends of the polymer chain, and (2) thereafter stretching and heat-setting the coated film, during which time the wet coating of the aqueous composition is dried and the polyurethane prepolymer is cured to form a thin cured polyurethane coating having a carbon-carbon double bond on the biaxially oriented polyester film.
U.S. Pat. No. 4,107,013 relates to an improved ultraviolet curable aqueous latex paint suitable for use as coil coatings comprising a high molecular weight primary latex binder in combination with minor amounts of an emulsified low molecular weight cross-linking agent adapted to cross-link the high molecular weight latex particles upon exposure to ultraviolet energy.
Generally, various amounts of polyfluorooxetane oligomers, polymers, or copolymers, which have one or two fluorinated side chains, or a copolymer thereof made from various cyclic comonomers such as oxirane, for example epichlorohydrin, monomers having a four member cyclic ether group such as oxetane, monomers having a five member cyclic ether group such as tetrahydrofuran can be reacted along with aqueous carboxylic acid dispersants, and with a polyol intermediate such as various polyesters, or polycarbonate polyols or other polyol intermediates, to form a polyurethane generally utilizing an excess of a polyisocyanate during an in-situ bulk polymerization. Alternatively, the polyfluorooxetane oligomers, polymers, or copolymers can be pre-reacted with two or more units of a dicarboxylic acid such as adipic acid to form an acid terminated polyfluorooxetane. This compound can be reacted with the polyol intermediate (such as a polyester) or desirably monomers forming the polyol intermediate (e.g. diacids and diols which form a polyester) to yield a polyfluorooxetane-polyol copolymer (e.g. a polyfluorooxetane-ester copolymer), which then can be mixed and reacted with the polyisocyanate along with the carboxylic acid dispersant. A neutralizing agent such as a tertiary amine reacts with the acid group of the carboxylic acid dispersant to form a salt, which renders the polyurethane dispersible in subsequently added water. The polyurethane can be chain extended in the aqueous medium whereby the polymer has amine end groups providing an aqueous dispersion of polyurethane particles which can be utilized as a coating having desirable properties such as chemical resistance, stain resistance, cleanability, a low coefficient of friction, good abrasion resistance, improved wetting and leveling, and the like. Upon the formation of an end use application, the acid and amine groups from the polyurethane optionally can be cross-linked as with thermal crosslinkers such as epoxies, polyisocyanates, carbodiimides or polyaziridines. The waterborne polyurethane dispersion or blend thereof can be applied as a coating to various substrates such as metals, plastics such as polyvinyl chloride, wood, fiberboard, pressboard, plywood, paper, or wall covering, and dried with heat.
Also, to the waterborne polyurethane composition can be added a free radical monomer or oligomer curable by actinic or by U.V. radiation such as various acrylates. A photoinitiator is desirably utilized in order to permit the free radical polymerizable monomers to be polymerized by ultraviolet light, electron beam, and the like. Generally, the aqueous polyurethane dispersion-free radical polymerizable monomer or oligomer blend is coated on a substrate and dried in order to eliminate water. The free radical monomers or oligomers are then polymerized by U.V. radiation and intermingled with the polyurethane to form a coating or laminate.